The 26-year-old has made a significant contribution on and off the field and in 20 starts to date has scored six tries, including two tries in all eight of Leinster's Heineken Cup games to date.
Commenting on being named the Leinster Player of the Year, Elsom said: "I have to thank the team for what has been such a great year.
"I've had a lot of support from the team and the coaching staff and it has been really obvious to me how much of an impact they've had on my season. I can't say enough how much I appreciate it.
"In particular I would like to thank Michael Cheika for getting me over here in the first place, because it took a hell of a long time and a lot of work, so I appreciated that effort.
"I liked Dublin a lot before I came to Leinster, but I didn't expect to have enjoyed it as much as I have and I would say the main reason for that is that I've really liked being around the team.
"The highlight of the year so far was the match last week against Munster at Croke Park.
"Also, the Leinster supporters have been fantastic all season. I would say that indirectly they are one of the major reasons why the team has been so successful.
"Their ongoing support of the club and the team has been extremely impressive.
"I have felt privileged to have come to a side that has such passionate and dependable supporters. It has made my time here that much more enjoyable and I cannot thank them enough."
Saturday's awards ceremony celebrated what has been another outstanding year for Leinster Rugby at all levels of the game.
Leinster and Ireland legend Dr. Bill Mulcahy was inducted into the Guinness Hall of Fame.
Mulcahy, a former UCD, Bective Rangers and Skerries captain, played on two Lions tours in 1959 (to Australia, New Zealand and Canada where he played in 15 of the 33 tour games) and the 1962 tour to South Africa (where he played in 17 of the 24 tour games including all four Tests, scoring one try).
In total he played 40 times for Leinster (1955 to 1969) and made 35 starts for Ireland over eight seasons, which included Ireland's first Test victories over Australia (1958) and South Africa (1965).
A hugely popular administrator, he became Skerries' first President of the Leinster Branch during the 1995/96 season, incidentally the inaugural year of the Heineken Cup.
Cian Healy picked up the Powerade Young Player of the Year award after a string of outstanding performances in both the Magners League and Heineken Cup competitions.
The Clontarf prop burst onto the Leinster scene at the end of the 2006/07 season and to date this season, he has featured in 23 senior games.
Progressive side Coolmine RFC, meanwhile, lifted the Canterbury Club of the Year after their first and second teams won their respective leagues, while their state-of-the-art facilities have been used extensively for key knockout Leinster Branch fixtures.
They continue to thrive at Minis and Youths levels and retain a strong local identity in the west side of Dublin.
Blackrock's Grace Davitt picked up the Philips Ladies Player of the Year award after an excellent season for club, province and country.
Terenure College, meanwhile, marked an excellent year where they won the Leinster Schools Junior Cup title and were also beaten finalists in the Senior Cup competition, by picking up the Powerade School of the Year honour.
Boyne's Seamie Briscoe was named the Evening Herald Club Public Relations Officer of the Year. Other individual winners on the night were Leinster trio Gordon D'Arcy, Jamie Heaslip and Paul O'Donohoe.
Meanwhile, Felipe Contepomi was presented with the Official Leinster Supporters Club (OLSC) Leinster Legend award on behalf of the supporters.
The award was presented on Friday night at the RDS as thousands of supporters gave him a fond farewell at the province's final home match of the season.
LEINSTER RUGBY 2008/09 AWARD WINNERS:
Bank of Ireland Player of the Year: Rocky Elsom
Guinness Hall of Fame: Bill Mulcahy (Skerries)
Powerade Young Player of the Year: Cian Healy
Powerade School of the Year: Terenure College
Evening Herald Club PRO of the Year: Seamie Briscoe (Boyne)
Philips Ladies Player of the Year: Grace Davitt (Blackrock)
Junior Club Player of the Year: Bernard Smyth (Navan)
CCC (Canterbury) Club of the Year: Coolmine RFC
Try of the Year: Gordon D'Arcy (v Munster, May)
Tackle of Year: Jamie Heaslip (v Glasgow Warriors, April)
Wagamama Noodler of the Year: Paul O'Donohoe
OLSC Leinster Legend Award: Felipe Contepomi